The ex-Lib Dem MP was doubtful the Government would be able to offer PSA – the owners of Peugeot – a similar “sweetheart deal” it offered Nissan to continue manufacturing in Britain.

He told BBC Radio 4’s Today programme “uncertainty” over the UK’s membership of the single market and the customs union was putting the 4,500 jobs at Vauxhall plants in Luton and Ellesmere Port at risk.

Speaking about Business Secretary Greg Clark’s chances of coming to an arrangement with the firm, he said: “He’s a very good minister and I’m sure he’ll do his best but he’s in a much more difficult situation.

“Because if big strategic decisions now have to be made by the combined group there is a new element of course which is the uncertainty of Britain’s participation in the single market and the customs union.

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Sir Vince Cable casted doubt over the Government safeguarding UK jobs

If you’re the new owners, Peugeot, you’re going to be extremely worried about what will happen when Brexit occurs

Sir Vince Cable

“Vauxhall are part of an integrated European operation, most of its exports go to the European single market, most of their components come from a European supply chain and if you’re the new owners, Peugeot, you’re going to be extremely worried about what will happen when Brexit occurs.”

Sir Vince dismissed suggestions the Government could broker a deal like it did for the Japanese car-maker.

Mr Clark reportedly assured bosses at Nissan it would not be subject to rising tariffs on car exports if the UK left the customs union without a free trade agreement with the European Union.

“We don’t know what they’ve offered Nissan,” said Sir Vince. “I think the only plausible offer to make Nissan that would persuade them to stay is Britain remains fully within the single market and the customs union in the automobile sector.

Remainers are finding it hard to accept Brexit.

He said PSA would have a “straight choice” between British and German plants if it was to make cuts.

“The Germans are going to put in a massive campaign to stop cuts happening in Germany,” said Sir Vince.

“There will be very intense political pressure brought to bear and the point they will make as well is: why on earth would you keep the British rather than German operations when there’s so much uncertainty about the UK and Brexit?”

He said: ”There is some way to go in discussions between GM and PSA, but I was reassured by GM's intention, communicated to me, to build on the success of these operations rather than rationalise them.”

Sir Vince said that "Vauxhall" could be the first major casualty of Brexit. The former Business Secretary was accused by one Radio 4 listener of being "defeatist" over the issue.

They tweeted: "Vince Cable on BBC Radio 4 is talking up the desirability/inevitability of Vauxhall UK closing #defeatist #brexit."